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April 16, 1929- J. D. LEWIS 1,709,134

ELEVATOR Filed Dec. '7, 1921 awuemoc 4 M 551 Que M4424 32 M PatentedApr. 16, 1929.

UNITED STATES PATENT orifice.

JACOB D. LEWIS, or YONKERS, NEW YORK; ASSIGNOR 'ro o'rrs sLEvAToRCOMPANY,

OF JERSEY CITY, NEW JERSEY, A CORPORATION on NEW JERSEY.

ELEVATOR.

AppFieation filed December .7, 1921. Serial No. 520,4 75.

My invention relates to controlling apparatus for electric currentmotors, more particularly as described and shown as .a controllingapparatus for alternating current motors for elevators.

:It has been found impractical heretofore in so when the motor-is run.on a-6O cycles current.

it is impractical to build the drivingor hoisting motor with agreaterspeed reduction than ,car running at- 600 F; P.,M.=as its high speed beapplied to bring the .car'to rest. Atthis ear speed of 200 F. P. M. themoving masses'of .the elevatorswould jstill have considerable; .kineticenergy with the result that the car would slide, making it dilficult to.secure fgoodTlanding S? and wouldalso result in rapid deteriorationof-the brake linings. The purpose of the present invention is toovercome these-and other obj ections in alternating current elevatorinstallations byproviding means whereby the car lowspeed is reduced. tosay one-ninth --of the high speed, thereby actually reducing the kineticenergy. of the moyingpartsto say; one eighty-first (1/81) partofitsenergy at high speed, so that no ditficulty is' experienced in makingrgood-stops and resulting in a long life of the brake liningsr I a IAnother object of the present invention I show with the use of aninduction motor as an auxiliary apparatusthat a-current of onethird(1/3) line frequency canbeobtained from its phase. wound .rotor so thatthe low speed winding of the main or hoisting motor 9 .can. be thrown onthis supply and thereby re duce its speed to one-third (l/3) For afurther ObjCCtOf the invention I employ the auxiliary induction motor asan 1111- I ,pedance in series with themaiu or hoisting motor for thepurpose of lin iiting the current to the hoisting mot-or, both. to itshighand low speed windings. This eliminates the stator v resistance,commonly used prior to my invention; the present means will decrease thepower consumption to a very considerable extentwhen there is a largenumber of starts and stops per'car mile.

. Other objects of the invention will appear hereinafter. r

This is primarilydue to the fact that .era'tor set. i I The accompanyingdrawing, illustrates 3 to 1. With this speed reduction an elevatorploying theus'ualhoisting motor in I an elevator, i together with.alconventional type of hoisting riggi ng and brake apparatus, a mainyoltage supply of a standardvalue at I a standardrfre uencyjor, tl1e,,motor, and a alternating current elevator installations to,' i

exceed a car speed of 400 F. P. M., especially imy invention;

I itrolledelevato y ariganged in accordance with would be retardedto 200F. P. M; car speed, at which point the mechanical brake would The,elevatoras shownin thedrawing comfp ri ses.a two s peed AQCf electrichoisting motor, M, of.theisquirrel cage-type, with two .stator.\gindings; supply ipains a b, c, from 5 whicl1l.an 'alte 'nating currentis supplied to e r iigl ils ef he tarlend he 'controlling mechanisms,-reversing switches, -U* and D,

. controlling; the phase relation ofcurrent sup- ,plied to themotor;electromagnetically operated switches,G,..E, H and I, electromag--netic brake; Bidiagrammatically shown, com lpr ising a plurality ofmagnet coils, a centrifjesall teee s eedv n r J J d matcallyshown,,comprising a plurality of switch contacts successively madeas the speed .ofithe motor increases and one contact opened after theothers are closed as hereinafter described, the governor being .drivenby the motor- 1H, through the vintermediation of a gearing lthegovernor.=when operating causing the successive operation of severalof the elements of;t l 1 e.controll1ng mechanism, as more fully-pointedout hereinafter.

The-different landings or stopping points aredcsignated L and L-, andthe car switch by the letter K, and the car leveling switch by theletter N. y

Referring now particularly to the supplementary or auxiliary controllingapparatus. itcomprises an induction motor, (hot the slip ring type,employed as a gencratm'. being drirenby another induction motor MQof thesquirrel cage type.- --Th eauxiliary apparatus, m'con unction with thecertain other elements heretofore referred to, is employed automaticallyto supply to the lowgspeed Winding of the hoisting motor. M,in'thestoppingoperation. low voltage at a low frequency, reducing thespeed of the saidwinding toaconsiderable extent, aat whichreducedspeed-the brake large number 'ofstarfts and stops per car mile.

All of which has been told heretoforefi There are two cams, .2 and 3,positioned in the elevator hatchway at each floor landing.

planes. The cams, 2,:are adapted to'opera'te contacts, 5, and cams, 3,contacts 4, of the car leveling switch, N these contacts controllingelectrical connections to reversing switches U and D, respectively, toeffect maintaining either reversing switch closed whenj the twistingmotor, M, is operating on the low ,"braiie magnet '13 at-the same time,receives current th'r'ough wires 56, j57'a'nd 58. and opvoltage, toeffect the automatic leveling operation of the car in a descending orascend-i ing direct-ion to stop at a landing, depending on the positionof the car relativelyto the.

cams, cons "itutinc the car leveling zone.

Operation of the elevator as a whole and through a complete cycle .ofoperation of starting and stopping will now be given. With the parts asillustratedin the drawing, the car is at rest, level with the second or-top floor landing. Let it be assumed that it is desired to bring thecar to the first landin n. by opera-ting the lever, 6, of'the car switchbeing thrown to an extreme-position, to the. left. as that is what- .anoperator or attendant would do in operating the elevator to cause it todescend, obtaining a full operatin n condition of the apparatus as a.result as will he sees] hereinafter. The operation of the car switchcloses first a circuit for the wieilin-gy'i. 0'1 thee'lectro-mag'netically 0p- 'ZlltWl low-speed switch. E. as follows: fromsupply main a. junction point 8. by wire 9, cnnlzr't 10. of thellP-ltVtlSlllg switch, U. by wirc 11. junction point 12-, by wire 13.junction point by wire 15. Contact 16, of the car switch K. segment H onthe car switch lcrcr (3. and contact 18 of car switch, as the contacts16 and l8 were bridged by the operation of the car switch lever 6. bywire 19. junction point 20. by wire 21. junction point 22. by wire .23.winding 7 of electromagnet switch E. by wire '24, junction point 25, bywire 26. junction point- 27. by wire 28. junction point- 29. by wire 30,junction point 31, by wire 32, junction point 83, to supply main b. Thewinding 7 of the electromagnet switch E is therefore energized and theswitch E closed. The closing-of the switch completes by its contacts, 34and 35, a, circuit for the down-reversing switch winding, 36,, asfolnot; starting at this-timeat the contact 16 closed, the contacts 47and .48 en ar ing conffaets and 50, respectively, and contact 51contactfizthe'back contacts'53 and "54 opening --through the operationof the The cams, 2, form one sel ies and the 'cams, 3, form anotherseries 1 arranged in"vertical I fjUQ-i when o'pen prevent an operationof "are u '-reversing switch, "likewise the contacts spoken of hereinbefore, when open, prevent an onmtion' of the down-reversing "switch'DffThe "closing of contact-s47, 18, 49

switch. The back contacts 5 3;arein circuit with the winding ofth-eHpr'eversing switch anus-o completes the circuit forthelow speedwindings of the hoisting motor; M. The

crates to lift the brake.

A switch, 55, ,will be closed {by hand throughwhich a source of supplyis obtained from the mains, a. b and c, for opemting the motor M". ofthe generator set, which motor M'. inturn operates the generator G.

Upon the closing of the contacts 47, 48, 49 and 50, of thedown-reversing switch, the stator'windings of the generatorG areexcited-as well as the'low speed stator windings of the hoisting motorM. Circuits through 'each'are'as follows: from main a, junction point 8,by'wire 59, contacts and 48, by wire 60,'junction point 61, by wire 62,junction point 63, by wire (it, junction pointfif), by wine through onestator winding of the generator G, by wire 67, contact 68. of switch I,by wire 69, junction point 70, by wire 71,

contacts 72 and 73 of low-speed switch E,

they are now closed, by wire 74, contact- 75 of switch C, by wire 76,through one lowspecd stator winding of hoisting motor M, by wire 77,junction point 78, by wire. 79, through the backfcontacts 8 of switch C,by wire 81. junction point by wire 8:3. junction point 84, by wire 85.through a second low-speed stator winding of hoisting motor M, by wire8(3, contacts '87, of switch C. by wire 88, contacts 89 and 90 of switchE, as they are. now closed as we said before, by wire 91. junction point92, by wire 93, contact- 94 of switch I. by wire 95, through a secondstator winding of generator G, by wire 96, junction 97, by wire 98.junction pcint'29, by wire 30. junction point 31, by wire 32, junctionpoint 33, to the main 6. The circuit for the remaining stator windingsof both generator G and hoisting motor M, is as follows: from nia-inc,junction point 99, by wire 100, through contacts 49*and-47 point 109,bywvire' 110, junction point- 111,

y wire 112, through'contacts 113 and 114 of switch E,'-asthey-are closedat this time, by

wire 115,'--contact-116 of switch-C, by wire 117, through a thirdlow-speed stator winding of hoisting motor M, bywire 118, contact 1190fswitch C,'bywire 120, through back contacts =121of. switch G, by wire122, unct-ion point 82, to the main-b as before traced, in thepreceding. case 'of the other stator I winding of'both'generator -andhoisting .n1otor t The-above illustrates that the operation .first ofswitch E,flsecondly, of either reversing stator windings of the hoistingmotor M, as well known to those versed n the motor art,

the impedance being of' a predetermined va.lu'e,' the-torque of thehoisting motor being *low a-t'this time results in a slow operation ofthe hoisting-motor at this time. The rotor winding ofthegenerator'is-open at this time and when' closed' by means of anelectromagnetically operated'low-speed accelerating switch,F,-theoperation ofwhich-will result in a change of the impedance in boththe. stator and rotor windings of the generator G which reduces thetotal impedanceto a smallervalue, as is well known; also to apredetermined "alue. The torque of the hoisting motor now being greaterthan it was, the motor increases its speed, and consequently the speedof the elevator car.

I have llustrated only one step of acceleration of the hoisting motorht, in my invention. that in which the operation of the low speedaccelerating switch, F,-eloses and consequently short circuits the rotorwinding oi the generator, G; but it is obvious that more. steps couldhoused with my system of con trol by the usef'of moreelectromagnetically opera-ted switches or other deviceseaeh to "cut outaresistance in series with the rotor winding of generator G, after whichlastly the rotor winding would be short circuited as in the presentcase. i The circuit for the winding'of the electromagnetically operatedswitch, F, is :as-followsz'from junction point 109, by wire 123,t-hroughthe closed back-contacts 124 of electromagnet switch H',by wire by wire131, contact 132 of e 125, through the winding 126 of electromagnetswitch F, by wire 127, through the closed governor J, contacts 128, bywire 129, contact 94 of electromagnet switch I, to the main Z), by wayof wire 95, stator winding of generator G, by wire 96, junction point97, by wire 98, junction point 29, by wire 30, junction point 31, bywire 32, and junction point 33. Thus the winding of switch F is subjectto the counter. E. M. F. of the hoisting motor. The

operation of electromagnet switch F, the contacts of which short circuitthe rotor winding of generator G, results in an increase of speed of thehoisting motor M, as told hereinbefore. The circuit is from the sli ring130,

lizctromagnet switch H, by wire 133, contacts 134 and 135 ofelectromagnet switch F, which are closed at this time, by wire 136,contact 137 of electromagnet switch H, by wire 138, slip ring 139; alsoslip ring 140, by wire 141, contact 142, of electromagnet switch H, bywire 143,'contacts 144 and 145, they being closed at this time, by wire14G, contact 135 back to the rotor as before. The closing ofclcctromagnet switch F makes a circuit by means of its contacts 147 and148, for the operation of the electromagnetically operated low and highspeed accelerating switch I. The circuit or the winding of electromagnetswitch I is as follows: from junction point 104, by wire 149, junctionpoint 150, by wire 151, through the winding 152 of electromagnet switchI, by wire 153, junction point 154, by wire 155, through closed backcontact 156, of electromagnet switch C, by wire 157, junction point 158,by wire 159, through contacts 148 and 147 of electromagnet switch F,they being closed at this time, by wire 160, unction point 27, to main1), by wire 28, junction point 29, by wire 30, junction point 31, bywire 32, and junction point 33. The operation of electromagnet switch Iin my controlling system, closing its three pairs of contacts as aresult. short circuits the stator windingof generator G, the remainingimpedance in series with the low speed stator windings of hoisting motorM has therefore been cut out, the torque of the hoisting motor hasbecome still greater and the result is a further increase of speed ofthe hoisting niotor. which is now operating on its low speed windingsalone. The contacts 161 and 162 o t the governor swit eh J wereoriginally open, but have closed during the operation of the h istingmotor M up to the. present stage, but. to which no e pecial significanceis attached at this time other than that theyhave closed.

- As a further operation in my system of con trol, there is theoperation of the electromagnetically operated high and low speed switchC, the circuit for its winding 167, is as followsz-froin contact- 16 ofcar switch K, the circnitup to thispoin't-from main a,being as beforetraced, segment 17 on the ear switch -lowand-high speed stator\\-'indings of the 'lloisting' motorfifare-inserie's with each other,together' with the stator windings of the generator G, as.-t-he'contacts of elcctrorhagnet switch C thereforecloses as a resultof the last-tracedcircui-t closin through the windng 16-7. Theelectromagnet switch C in operating firstzopens its normally closed orback cont-acts, aften'which for an instant both, the

switch I, which iira. previous operation shortcircuited the saidwindingsof the generator, are again open as the opening of one of the bacl'rcontacts of electromagnct switch C has deenergized theelectromagnetswitch I The top or normally open-contacts of eleetromag; net'switchC-inclosing short circuitsthe low speed stator windings-of (he hoistingmotor M. It thus follows that the high speed stator windings ofthe-hoisting motor M, have been energized',;and that the stator windingsof the generator G have? been put in circuit with thehigh speedstator-windingsof the hoisting motor M, and actasanimpedance to these.windin s (as the stator windin s of the generator did with the lowspeed stator wind- -.ings of the hoistingmotor M. As a consequence, thespeed or 'the hoisting motor M is further increased as aresult of theenergizing of the high-speedwindings of the said -motor; the-circuitforthecurrent to the high speed stator windings'ofi-the hoisting motor atthis time is froni original supply main '0, to junction point-lOeh-anchthence by wire 105, through a stator winding of generator G, by wire106, contact 107 of electromagnet switch I, by wire 108, junctionpoint109, by wire 1 10, junction point 111, by wire 112, contacts 113 and 111 of-rele'ctron'iagnet switch E, by wire 115, contacts 116 and 119 ofelectromagnet switch C, as they are now closed, by wire 118, throughahigh speed stator winding of the hoisting motor M, the windings beingconnected together at one of their ends which I have shown, we gothrough another high speed stator winding, by wire 85, unction point 84,by-wire 169, contacts 170 and 87 of clectromagnet switch C, by wire 88.contacts 89 and 90, of electromagnet switch E, by wire 91, unction point92, by wire 93, contact 94 of electromagnet switch I, by wire 95,through a stator winding of generator G, by wire 96, j unction point 96,by wire 98, junction point 29, by wire 30, junction point 31, by wire32, and-junction point 33, to main 6. The circuit for the remaining highspeed stator windings of the hoisting motor is originally from supplymain a, to junction point 65, and thence by wire 66, through a statorwindings of generator G, by wire 67, contact-6'8, of electromagnetswitch I, by. wire 69, junction point 70, by wire 71, contacts 72 and73,-of electromagnet switch E, by wire 74, contacts and 171ofelectromagnet switch G, by wire 172, junction'point 78, by wire 77,through a high speed stator winding of hoisting motor M, and since allthe high speed windings are joined together at one of their ends, thecircuitpasses through the wire 85, to the main 7/ as previously traced.

The contacts 173 and 174: of the governor switch J, have closed, due tothe increase of speed of the hoisting motor M, after its high speedstator windings were energized, the closing of the said contacts servingfurther to increase the speed of the hoisting motor M, .by making acircuit for operating again the el ectromagnet switch I, which as shownbefore when the contact of the said switch are closed short circuit thestator windings of generator G, which acted as an impedance to thecurrent to the low speed stator windings of hoisting motor firstly, andto the current to the high speed stator windings of the said motorsecondly. The circuit through the electromagnet switch I at this timeis, from unction point150, the feed coming from main c, to this point,by wire 151, through the winding 152, of the switch, by wire 153,junction point 154, by wire 175, contacts 176 and 177, of eleetromagnetswitch C, as they are closed at this time, by wire 178, contacts 173 and174 of governor switch J, by wire 179, contact 147, of electromagnetswitch- F, by wire 160,- junction point 27, by wire 28, junction point29, to main I). The speed of the hoisting motor M, increasing afterthecontacts 173 and 174 of governor switch J have closed, the hoistingmotor M is now operating on full torque and consequently at its highspeed to bring! the illf-Y i r car to the first ianding L. The contactsof governor switch J open as a result. deencrgizing electronmgnet F, therotor windings of g'aierator G, being opened as a result.

In stopping, the car switch lever 6, is brought to center and whennormally done so the operation is as follows: first the electromagnethigh and low speed switch C will he deenergized, opening the circuit tothe high speed stator \\-'indings and closing the circuit to the lowspeed stator windings of hoisting motor M. The-eiectromagnet low andhigh speed accelerating switch I will open as a re have decreased to apredetermined value, resulting in closing the contacts 128 of thegovernor switch J, the rotor windings of generator G will remain open,there will be then the maximum impedance in windings of the generator G,in circuit with the low speed stator windings of the hoisting motor M,which causes the motor to slow down quickly.

It will be observed that the generator G statorwindings are insertedduring the slowdown period, because at that time, the torque of thelowspeed stator windings of the hoisting motor M will be excessive, andtherefore an eflicient Inethod'of reducing the voltage in thehoisting-motor M is necessary. The contacts 128 of thegovernor switch Jwill have closedby this time, after which only thestator windings ofthegenerator G are in circuit with-the low. speed windings of the hoistingmotor;M. The car switch K may have. been centered by this time, but itwill be assumed that the speed of the hoisting motor M, is still greatenough to hold closed the contacts 162 of the governor switch J, throughwhich a holding circuit is established to hold. closedthe electromagnetlow. speed switch 'E, the circuit being had from junction point 12,bywire 180,through contacts 162, by wire 181, junction point 22, to andthrough the winding '7 of electromagnet switch. E, to main 6 as before.The contacts 161, of governor switch J, likewise -not'hav.- ing. openedas .yet provide 'a. holding circuit for-the down-reversing switch D,circuit is :asl follows: from junction-point 12, byv wire 180, left hand'cont-act 162, by wire 182, conta'cts 161, o fgovernorswitch J, by wire183, junction point 184,-by wire 185, contacts 52 and :'51- ofdown-reversing switch D, by wire 188, junction point 43, through thewinding 36 of reversing switch to main 1) as before. Governor switch J,contacts 162, opening at this-time, the electromagnet switch E, openingas a result, cut-soutof the circuitof the lowspeed stator windings ofhoisting motor M, the stator windings of the generator in the circuit tothe windings of the hoisting motor M. The circuit to the stator windingof the generator G is now through the closed back contacts 209 and 210of the clectromagnet low speed switch E. Through the other closed backcontacts 189, a circuit for the operation of the clectromagnetdecelerating and micro-switch H, the circuit of which is as follows:from the junction point 63, by wire 190, through the winding 191 ofelectromagnet switch H, by wire 192, through closed back contacts 189,of electromagnet switch E, by wire 193, and junction point 102 tomain'c. The'back contacts 124 of electromagnet switch H, in openingdeenergize electromagnet low speed accelerating switch F, resulting inthe rotor windings of generator G being again opened. The closing ofcontacts194 and 195 of electromagnet switch H closed one side of thecircuit for the downreversing switch D. The Circuit for the reversingswitch D now being from junction point 44, by wire 45, contact 34, ofelectromagnet switch E, by wire 196, through contacts 194 and 195 ofelectromagnet switch H, by wire 197, junction point 27, by wire 28, andjunction point 29, to main b, as before. During the interval between theopening of electromagnet low speed switch E and the closing ofelectromagnet decelerating switch H, the circuit ,for thereversingswitch D was through the resistance 198. The reversing switch therebybeing kept closed during the change-over period. The closing of contacts137 and 199, 142 and 200, 132 and 201 -of electromagnet switch; H,placed in circuit with the low speed stator windings of hoisting motorM, rotor windings of the generator G, which now delivers a current tothe said windings of the hoistingmotor M, the circuits are as follows:from slip ring 130, by wire 131, contacts 132 and 2010f electromagnetswitch H, by wire 202, contact 73, of electromagnet switch E, by wire74, contact 75, of electromagnet switch C, by wire 76, tl1rough a lowspeed stator winding of hoistin motor LI, by wire 77, junction point 78,y wire 79, back contacts 80, ofelectromagnet switch C, by wire 81,junction point.82,'by wire 83, junction point84, by wire 85, through alow speed stator winding of hoisting motor M, by wire 86, contact 87, of'electromagnet switch C, by wire,;88, contac ts '89, of electromagnetswitch E,- -by wire203, through contacts 200 and 142, ofelectromagnetswitch H, by wire 141, to slip ring l40..', .-A lso -from slip ring-139, by wire 138, through-contacts 137 and 199, of electromagnetswitchH, by wire 204, Contact 1140f electromagnet switch E, by wire 115,contact 116, of electromagnet switch C, by wire 117, through a low speedstator winding of hoisting motor M, by wire 118, contact 119 ofelectromagnet switch C, by wire120, through back contacts 121 ofelectromagnet switch C, by wire 122, junction point 82, back to therotor of generator G, as traced before.

The generator G is supplying to the low speed stator windings ofhoisting motor M power at a very low frequency, which results in a veryslow operation of the hoisting motor and elevator car. For example, itwill be assumed that the main supply line is 60 cycles current, andauxiliary motor M, which is a low resistance squirrel cage motor, andgenerator G are wound for 6 and 4 poles, respectively. The synchronousspeed of mo- .tor M is 1200 revolutions per minute. Then the frequencyof the rotor current of generator 6 4 1200 G X F)- 20 cycles.

The result of the exchange of energy of the motor M aird-geri'er'atorG,can he easily com put-ed being the power delivered 'to the hoist, ingmotor for operating; Knowing duty or load of'the elevator,-spee d,counterweight andother constants, thelpower delivered'by the genera torG to the lowspeed statb'r wind ings of l1oisting-inotor'.Miseasilyobtained by'lthose versed in the elevator art.

' Assumethat 'thegovernor switch J, contact 161, open 'upon thearrival-lot the-elevator ear-in the leveling zone; circuit to maintainthe down eversing' switch *c'los'ed at this time is from:- 'jun'c'tionpoint 12,;by wire 13,-junction point 14;, through contacts 5, ofthe-leveling switch N,--as'ithey-are=now closed, the roller 205,'ef theswitch N having engaged cam 2, closing' he contacts 5 as a result, bywire 2-06, junction point 39, to undfthroug'h the down-reversingswitchD, winding 36, as before traced, the'other side of the circuit "from thereversing switch winding being traced through the'contaets 194 and 195of theelectromagnet switch H ,as they are still closed. The elevator carplatform coming opposite to the "landing L, whereupon the roller 305 ofthe leveling switch N rides oil of the cam 2, opening the switchcontacts 5, and efl'ects the opening of the down-reversing switch D, andthe electromagnet decelerating switch H. "In'this mannerall theelectrical circuits to :the hoist: ing motor M, genei aton G, brakewinding, etc., are opened, and the bra ke'shoe is applied to bring theelevator car to rest.

n In the eventof"the caroverrunning the landing, contacts ief switch Nwill be closed by the roller -205 engaging cam 3 whereby circuitssimilar tofthose described for the down lowspeed operation'by generatorG will be closed to return the car to the floor level.

I have described my invention in connection with. the operation of thedown-reversi ng switch I). but it will be understood that the operationis the same in principle when the up switch U is operated.

In order to simplify the illustration and (.lcscription. I have omittedfrom the drawing the usual safety devices such as the limit switches atthe upper ends of the hatchway, the emergency switch in the car, thedoor contacts, etc, as they are unnecessary to illustrate my invention.

It will be understood that my invention is adapted for use with othertypes of elevator control than the one herein shown as for example,but'not to exclude others, a push button elevator. I desire not to belimited to any particular number of low speed accelerating switches F;they may be as numerous as desired, the greater the number used thegreater the refinement'of operation will be. Furthermore, I have for thesake of illustration shown a three phase system of alternating current,but my invention is not confinedto'any particular number of phases;'Furthermore,'I wish it to be understood that my invention is notlimited to the details of construction or arrangement of parts hereindisclosed, and that various modifications might be made Within thespirit and scope of the invention.

I claim:

' 1. In an elevator control system, the com bination of an A. C.hoisting motor of the squirrel 'cage type, with statorwindings, a

source of power of a certain voltage and froquenc'y, means'adapted toconnect-said source to the stator windings of the hoisting motor, amotor-generator set adapted to supply the hoisting 'motorf-with'power ofa low voltage an'dlow frequency as'compared with the volt age andfrequency of said source, and speed responsive means adapted to -connectthe generator of themotor-generator set to the hoisting motor at adefinite speed of the hoisting motor.

2. In an elevator-control system, the combination of a multispeed A.C.-'hoistingmotor comprising "low speed stator windings, anelectro-mechanical brake therefor, a source of power of a certainvoltage and frequency, a motor-generator set comprised of a squirrelcage motor and a slip ring motor, the squirrel cage motor being adaptedto drive the slip ring motor causing it to produce a low voltage of lowfrequency as compared with the voltage and frequency of said source, andspeed responsive means adapted to eifect'a connection between themotor-generator .set and the low speed stator vwindings of the hoistingmotorin the operation of stopping the elevator, whereby the speed of thehoisting motor is reduced, and-at which reduced-speed theelectro-mechanical brake can be applied to'cause a good stop of theelevator car to be made at .a desired floor landing.

3. In an elevator control system, the combination of a multi-speed A. C.hoisting motor having low speed stator windings, a source of power of acertain voltage and frequency, a motor-generator set adapted to producea low voltage at a low frequency as compared with the voltage andfrequency of said source, and means for connecting the generatorwindings in series with the low speed stator windings of the hoistingmotor as an impedance in the operation of starting and stopping theelevator, whereby the flow of current from said source to the hoistingmotor is limited.

' 4. In an elevator control system, the combinationof a multispeed A. C.hoist-in motor having low andhigh speed stator win ings, a source ofpower of acertain voltage and frequency, a-motor-generator set adaptedto produce-a low voltage at a low frequency as compared with the voltageand frequency of said source, and means for connecting the generatorwindings in series with the low and high speed stator windings of thehoisting motor stator windingsRaliminatedJ the 1 elevator, whereby theflow 5 of? currentfrornsaid' source to the 'hoisting motor -is limitedand seirternal' resistances for the 5. In an elevator-control' system,the combinationof an A: C: hoisting motor having low 'andhighspeed'stator-winding s, a main high} voltage supply; for the-motor,- an A. :C.auxiliar'y generator ofth'e'slip ring'type, anelevator-lowspeed-switchadapted to connect in seriesthe'staton-windings of the' a-iixiliarygenerator and the; low-'spee'd stator windings of; thehoistm'g -"motor,' anelevatorf low 3 speed acceleratingswitchadapted to'short circuitthe rotor w-indings of the auxiliarygenerator, an elcva'tor lowwnd highspeedaccelera'ting switch adapted' to short fcir euitthe stator windingsofgthe' auxiliary' generator,'-'and an elevator high anddow speed switchadapted, whennone of its-contacts :are' closed, to place the =highispeedstator'wvindings o= the hoisting motorimseriesazwith low: speed statorwind'ng's and the-'.-statorwindings lot the auxiliary generator and,when certain of its contacts are closed, to short circuit the-low speedstator windings :of the hoisting motor. {[n anelevator control system,the-combination otmar. G hoisting .motor .having low andhighspeed-stator winclings,-a'main voltage supplyzfog the -motor, an A.C. auxiliary,--generator:ofizthe slip; ringi typefan ;.ele-, vator lo'w"speedl'switch'adapted' to connect. in series zzthe statorrswfndings.rof: theauxiliary generator and the low speed stator windings of :the,lioi sting.;mhtor;:an elevator-110w. speed accelerating-[sw tchadapted-"to short -oirc uit the.-rotorlizviindingsioiithiauxiliary;generator, an ;elevator ilow and hi'gh speed accelerating switch:adapted to shortycircuit the stator windings, of the: auxiliarygenerator; an elevator.-l1igh.:and.-:low speed. switch adapted,when-noneiof-its contacts are closed, to place the high speed;sta.-torwindings of the hoisting motor-in series withits-low speed statorwindings and the stator-windings of the aux iliary generator andgwhen'certain of its contacts are closed, to short circuit the low speedstator windings of the hoisting motor, and an elevator. governor. switchadapted, when closed, to effect-the short circuiting of thestator-windings of the auxiliary generator.

7.:In an elevator control -system, the combination of an A. C. hoistingmotor having low and highspe'ed stator windings,a main voltage supplyfor the motor, an A. C. auxiliary generator-of the slipring type, anelevator low speed switch adapted to connect in series thestatonw'indings of the auxiliary generator and the low speed statorwindings of the hoisting'motor, an elevator low speed acceleratingswitch adapted to short circuit the rotorlwindings of=the auxiliarygenerator, an elevator low and high speed accelerating switch'adapted to"short circuit the stator windings oithe auxiliary generator,

an elevator high and low speed switch adapted, when none of its contactsare closed, to

place the high speed stator windings of thehoisting motor in series withits low speed stator windings and the stator windings of the auxiliarygenerator and, when certain of its contacts are closed, to short circuitthe low speed stator windings of the hoisting motor, and an elevatorgovernor switch 'comprising two sets of conta is, one set adapted, whenclosed, to effect the short-circuiting of the stator windings of. theauxiliary generator,- and the other set adapted, when open, to effectthe opening of the rotor windings of the auxiliary generator. 4

' 8. In an elevator control system, the combination of an A. C. hoistingmotor having low and high speed stator windings, a main voltage supplyfor the motor, an auxiliary generator having stator windings adapted tobe connected in series with the stator windings of the hoisting motor,an elevator electro-magnetically operated hi h and low speed switchadapted to open the circuit between the main voltage supply and the highspeed stator windings and close the circuit between the main voltagesupply and the low speed stator windings in the operation of retardingthe elevator, an elevator low :rnahsm and lowspeed switch and to insertthe stator windings of the auxiliary generator in series withf'the'low-speed stator-windings of the hoisting motor, an elevator low speedswitch adapted, when opened, to cut the stator windings of the generatorout of the circuit of the low 'speed-stator.windings of the hoistingmotor, and anelevator governor switch having contacts adapted, whenopened, to open the elevator low speed switch. Y

In an elevator control system, the combination of an A. C. hoistingmotor having low speed stator windings, a main high voltagesupply'therefor of standard value and frequency, reversing switches forthe elevator, an auxiliary generator, having stator and rotor windings.and adapted to generate a current of low voltage at low frequency ascompared with that of the main voltage supply for the hoisting motor, aswitch operable to open the circuit between the main voltage supply andthe hoisting motor, a switch adapted to close to connect together therotor windings of the auxiliary generator and the low speed statorwindings of the hoisting motor, and means to maintain closed onereversing switch during the period between the opening of said firstnamed switch and the closing of said last named switch.

10. In an elevator control system, the combination of an A. C. hoistingmotor having low speed stator windings, a main high voltage supplytherefor of standard voltage and frequency, elevator reversing switches,an

auxiliary generator having stator windings and rotor windings adapted toproduce :1 current of low voltage at low frequencyas compared with themain voltage supply for the and thelow .-speed -:stator windings of thehoisting motor, and means automatically operable to open theclrculttothe hoist ng motor.

prising low; speed stator windings, an electro-mechanicalibltl'ke, a;main "high voltage supply of a standard value at a standard fre--'-quency, an'A. C. moto r generatpnsetecomprised of a squirrei-cageand-nslip r ng inotor, the squirrel cage motor adapted-to dr ve the slipring-motor causing it to produce a low voltage of low frequency, anelevator low speed switch-adaptedto eliect aconnection between theinduced-windings of-thc slip ring motor and the low speed stator wipdings of the. hoisting motor; in the pperatron of stopping the elevator,whereby the 5 speed of the hoisting motor is reduced; and atwlncnreduced {speed the electric-mechanical (brake can be appliedto-cause agood-stop of-jthe ele- 12. .-In an elevator control system, ;the -con 1-bination'oiazn A. G. hoisting motor,--.compr i s ing lowjspeed statorwindings, an-electromechanical brake,.a main l1igh voltage supply of astandard-valueata standard frequency, an A. C. motorrgeneratorset1comprised ofa squirrel cage-and a .slipring motor, the squirrel cagemotor adapted to drive the slip ring motor causing it to ,produce a lowvoltage of low frequency, means adapted to disconnect the hoisting motorfrom the high voltagesupply, and means to connect the induced windingsof the slip ring motor and the low speed stator windings of the hoistingmotor in the operation o-fstopping the elevator, whereby the speed ofthehoisting motor is reduced, and at which reduced 'speed theelectro-mechanica'l brake can be applied to cause a good stop of theelevator car to be made at a desired floor landing. e

13. In an elevator'control system, the combination of an A. C. hoistingmotor, comprising low speed stator windings, an elect-some chanicalorake, a main high voltage supplyo'f a standard value ,1! standardfrequency, a. motor-generator set comprised of a squirrel cage and aslip ring motor, the squirrel cage motor adapted to drive. the slip ringmotor causing it to produce a low voltage oflovv.

slip ring-motor and-the low speed stator wind-- ings ofthehoistingmotor; in the-operationof stopping the-,elevator, whereby thespeed of the hoisting moto-ixisrediiccd, and at which reduced speed theelectro-mechanical brake cambe applied'to ceu'seagood stop of theeleevator cart-o be made at a desired floor landing.

-14. lil-anielovator controhsystem, the combination of an .A. .G.hoisting motor, a. main voltage supply there-forofv'a standard-value atr i ast'andard frequency,; an A.C.aufxiliary gen- 11. In an elevatoreontrolsystem, the com-' binationoi-an A. C. .holstmg motor, com-'orator, meansadapted to connect in 'series the stator. .ivindingssof thehoisting' motor j andauxiliary generator, the generator having openrotor windings,- and means adapted to short circuit the stator windingsand rotor Windingsof themmx i'liary generator. ,ifiijln-anielevatorcontrol system, the coln- "aina'tion of an 1L0. hoisting motor,- havinglowspeed stator windings,a main voltage supply there-for of standardvalue at a standard frequency, an A. C: auxiliary generator, meansadapted toconnect iii-series the low speed stator-windings of thehoisting-motor and the auxiliary generator, nthe; generator having openrotor zgvinding.s,and meansadapted-to short :circuit. the rotorivindings of the auxiliary generatoryinsthe operation of startingtl13aleV3tOl. .=i 16. Inan. elevator: control system, the com binationof an A..=C. hoisting fmotoiihaving low speed stato it windings, amainvoltagesup plytherefor dfa standard value at'a standard frequency,and a [system of control for the hoisting. motor, comprising an A. C.auxiliary generator, an elevator -lo\vspeed switch adapted to connect inseries the' stator Windings of (he auxiliary generator and the low speedstator windings of the hoisting motor, and an elevator low speedaccelerating switchadapted to short circuit the rotor wind ings of the.auxiliary generator, in the operationof starting the elevator.

'17. In an elevator control system, the combination, of an A. 'C.hoi'sting motor having low speed-stator windings, a main voltage supplytherefor of a standard value at a standard frequency, and a system ofcontrol for the hoisting motor, comprisingan A. C. auxiliary generator,an elevator low speed switch adapted to conncctin series the statorwindings of the auxiliary generator and the low speed stator windings ofthe hoisting motor, an elevator low speed accelerating switch adapted toshort-circuit the rotor windings of the auxiliary generator and meansadapted to short circuitthe stator-windings of the auxiliary generator.

18. In-an -elevator control system, the combination of an A. C. hoistingmotor having low speed stator windings, a main voltage supply thereforof a standard value at a standard frequency, and a system of control forthe hoisting motor, comprising an A. C. auxiliary generator, an elevatorloW speed switch adapted to connect in series the stator windings of theauxiliary generator and the low speed stator windings of the hoistingmotor, an elevator low speed accelerating switch adapted to shortcircuit the rotor windings of the auxiliary generator, and an elevatorlow and high speed accelerating switch adapted to short circuit thestator windings of the auxiliary generator.

19. In an elevator control system, the combination of an A. C. hoistingmotor, a main voltage supply therefor, and a system of control for thehoisting motor, comprising an A. C. auxiliary generator, means adaptedto connect in series stator windings of the hoisting motor and auxiliarygenerator, the generator having open rotor windings, means adapted toshort circuit the rotor windings of the auxiliary generator, and meansadapted to short circuit the stator windings of the auxiliary generator.

20. In an elevator control system, the combination of an A. C. hoistingmotor having low and high speed stator windings, a main voltage supplyfor the hoisting motor, and a system of control for the hoisting motor,comprising an A. C. auxiliary generator, means adapted to connect inseries the stator windings of the auxiliary generator and the low andhigh speed stator windings of the hoisting motor, the generator havingopen rotor windings, and means adapted to short circuit the rotorwindings of the auxiliary generator.

21. In an electric elevator control system, the combination of amulti-speed motor for raising and lowering the elevator car, a mainpower supply of a given frequency for said motor, means for effectingthe various speeds o t said motor by suitably connecting its windings tosaid main power supply, an auxiliary power supply of a differentfrequency for said motor, and means for leveling the car with a desiredfloor, said means comprising automatic means for effecting still anotherspeed of said motor by suitably connecting its windings to saidauxiliary power supply.

In testimony whereof, I have signed my name to this specification.

JACOB D. LEWIS.

